1. Field of the Invention
The invention relates to a fuel filter, and more particularly, to a filter for use with diesel fuel, and in particular, to a water separating fuel filter.
2. Brief Description of the Prior Art
In U.S. Pat. No. 4,986,907, it is stated that the design of the filter is such that the interior fuel flow conduit is an elongated pipe whose perpendicular arrangement with respect to a longitudinal axis of the intake orifice allows a first impact of the fuel that enters the apparatus through the intake orifice. On flowing out from the interior pipe 30, the fuel hits against metal plate 50 (sectioned vertically in FIG. 3), which runs diametrically and also substantially longitudinally around the interior of the cylinder. While the diesel filter of the patent does a credible job of removing water, it is an expensive structure and does not remove trace portions of water. It also fails to completely separate water if the water is accumulated as a large slug. Also, entrapped air interferes with the water separation process.
According to the patent the fuel that leaves pipe 30 and hits against the plate is projected centrifugally to create a turbulence that initially facilitates separation of its components such as water, sulfur, sulfuric acid, etc. which, due to their greater specific weight in relation to the (diesel) fuel tend to be precipitated toward the bottom surface of cylinder 10.
The concept of using centrifugal force to facilitate fuel/water separation, is also found in U.S. Pat. No. 4,780,203, in which fuel flows obliquely downward to generate a rotational flow promoting separation of the denser water fraction from the fuel. An upturned lip is provided to collect water droplets that drift down the outer surface of the outlet conduit.